Negative magnetoresistivity in holography

TL;DR

This paper investigates negative magnetoresistivity in holographic models with magnetic backreaction, revealing how axial charge dissipation and backreaction strength influence magnetoconductivity and its scaling behavior.

Contribution

It provides a holographic analysis of magnetotransport properties considering backreaction effects and axial charge dissipation, extending previous probe limit results.

Findings

Quantum critical conductivity increases with magnetic field beyond a critical backreaction strength.

Negative magnetoresistivity appears with axial charge dissipation.

Magnetoconductivity scales linearly with B at large fields, deviating from B^2 scaling.

Abstract

Negative magnetoresistivity is a special magnetotransport property associated with chiral anomaly in four dimensional chiral anomalous systems, which refers to the transport behavior that the DC longitudinal magnetoresistivity decreases with increasing magnetic field. We calculate the longitudinal magnetoconductivity in the presence of backreactions of the magnetic field to gravity in holographic zero charge and axial charge density systems with and without axial charge dissipation. In the absence of axial charge dissipation, we find that the quantum critical conductivity grows with increasing magnetic field when the backreaction strength is larger than a critical value, in contrast to the monotonically decreasing behavior of quantum critical conductivity in the probe limit. With axial charge dissipation, we find the negative magnetoresistivity behavior. The DC longitudinal magnetoconductivity scales as $B$ in the large magnetic field limit, which deviates from the exact $B^2$ scaling of the probe limit result. In both cases, the small frequency longitudinal magnetoconductivity still agrees with the formula obtained from the hydrodynamic linear response theory, even in the large magnetic field limit.